Extreme Makeover: Citi Consolidates 70 Data Centers to 20

The global bank has also virtualized 40,000 servers and improved server utilization by 45 percent.

Citi has increased its utilization during a time when the volume of transactions and data continues to increase. "The nature of business requirements has not changed and we have seen a 15% increase in volume across all businesses," Rao says. "We process greater volumes, but size of the transactions is smaller." For instance in the trading business, the trading volume has increased although the order ticket size has decreased.

Similarly, "If you look at the credit card business, the number of transactions is skyrocketing, but the average size of the transaction is much smaller," Rao notes. But when it comes to data center capacity, a large credit card transaction for a flat screen TV at Best Buy is treated the same as a purchase of a cup of coffee at Starbucks.

Citi also has increased its storage utilization to 60%, up from 10% a few years back. "Modern technology allows you to do this," Rao says. "When you run it as a massive shared infrastructure, there are benefits to the scale. Essentially, we are running a huge private cloud." Increasing storage utilization only a few percentage points brings huge benefits for Citi, considering it has 72 petabytes of data in its data centers.

One form or modern technology that Citi is using in its data centers is newer solid state memory (SSD), or flash memory. Although SSD accounts for only one percent of Citi's overall storage capacity, according to Rao, firms typically use SSD to improve performance and even reduce costs.

Jeff Richardson, executive vice president and chief operating officer at LSI Corp., a provider of flash storage and other flash solutions to enterprises, told Wall Street & Technology that flash storage may "increase the cost of the server by 10 percent." However, the improved performance and reduction in the need for the number of servers because of the flash technology, should lower the overall cost to an enterprise, Richardson says.

Cloud On Hold
Citi's massive private cloud is one reason why Rao says Citi isn't looking at external cloud providers at this time. "Since we have increased our data center efficiency, we have not found the economic rationale" to move to the cloud. "Today, the cloud solutions do not give us the flexibility or the cost savings."

Also, Citi isn't convinced that external cloud solutions will meet its compliance needs. "We constantly evaluate all of our options," he says. "But when it comes to the cloud, there are data privacy issues and regulatory constraints" that Citi feels have not been sufficiently addressed by external cloud providers.

For instance, Rao says Citi could actually reduce its data center footprint even further, but it must keep 10 satellite data centers to comply with personal data privacy regulations. "If there were no regulatory constraints, I could run the entire infrastructure in 10 data centers," he says. "The 10 satellite centers are run in certain countries to comply with local regulations."

Also, by running data centers at just 50% of capacity, Rao says Citi can efficiently move transaction processing load across the globe when needed. "At 50% capacity, we could move [transaction load] back and forth," he says. "We are operating 24/7. Workloads are shipped back and forth between the US and Asia, and that makes the infrastructure work more efficiently."
Greg MacSweeney is editorial director of InformationWeek Financial Services, whose brands include Wall Street & Technology, Bank Systems & Technology, Advanced Trading, and Insurance & Technology. View Full Bio